1. Field of the Invention
The present invention relates to a technique for controlling progress of a video game played on a player terminal, which a player operates, via a communication network.
2. Description of the Related Art
Heretofore, various kinds of so-called online games are presented. Such an online game is supplied to a player terminal via a communication network such as the Internet. Further, in a role playing game as the online game (RPG; that is, a game in which a player plays a role of a character in a world of the game, and accomplishes a predetermined object while enjoying a process that the character grows through various experiences), a plurality of players may respectively operate a plurality of player characters, and the plurality of player characters may appear in the same field of a virtual world on the game at the same time. In this case, the plurality of players can experience the same event at the same time.
This online game allows the player characters existing in the topographically near place on the same field to view the other player characters mutually. In addition, the online game allows the player characters to make contact with the other player character such as make a conversation on the field. One specific interest in the online game is that other player characters operated by other players appear on the same field in this manner and the game proceeds together.
On the other hand, other player character operated by a third person who is unrelated to oneself however may strike down a boss character in a battle scene with the boss character, for example. This result in remarkable harm in interest in the game for the player who wants to strike down the boss character by himself.
Moreover, for example, in the case where a virtual world on the game has broken by the player character operated by any player, this results in influence on all of the other players who respectively operate other player characters existing in the same virtual world.
In order to prevent harmful influence as described above, the online game is devised so that all of the players can experience an important event by shutting the sharing of the game world from the other players at timing of encountering an important scene (such as confrontation with the boss character), and setting an area called a “private area” for every player or party.
This private area is accomplished by creating the same number of instances (copies) as that of players (or parties) dynamically. The instance includes map data required for a specific area when the player character moves in the specific area on the game world, and data on an enemy character and the like.
Thus, there has been a problem that processing load of an online game providing server for providing the online game is increased when a large number of players access an area or event that is an object to create a private area at the same time.
In order to reduce the load of the online game, various technologies are proposed for games in which a story is developed in high-load form against the server (in particular, a massively multiplayer online role playing game (MMORPG)).
For example, Japanese Patent Application Publication No. 2001-232068 discloses that the load of a server is reduced by executing communication for only important information such as acquirement and/or exchange of item(s) and attack against an enemy character and not executing communication for data other than the important information (such as movement of a player character).
Further, Japanese Patent Application Publication No. 2002-183762 discloses that the load of a server is reduced by setting the upper limit of the number of player characters to be displayed on a screen, and not reflecting (that is, not executing communication) data on excess player characters even though the number of player characters existing in the same area exceeds the upper limit.
Moreover, Japanese Patent Application Publication No. 2004-298373 discloses that the load of a server is reduced by determining congestion degree of an area on the basis of the amount of data for sending and receiving chats, and gradually increasing or decreasing a communicatable area in response to the determined congestion degree.
However, in the private area of the prior art described above, an instance about all of the data used in the area is created for each of the players (or parties). Thus, there is a problem that a server resource of the control for the private area is increased in proportion to the number of players (or parties).
Further, the load of the server is somewhat reduced using the technique disclosed in the Japanese Patent Application Publications described above. However, since the processing load of the server for providing an online game is still great amount, it is expected to reduce the load further.